ci: Use Python virtual environment in "x86_64-macos-native" job #1771

Fixes #1768.

This PR explicitly sets up a virtual environment instead of using uv, as suggested here, for the following reasons:

1. It does not require granting a third-party action access to the repository.
2. This approach is already used in other parts of the CI framework (it’s unclear why it was missed in #1359 in the first place).

utACK d3ae05447429d66b065ce3982fb0c5864c18bb53

Let's wait for green.

Thanks for fixing CI so quickly. :)

I agree, that's simpler and does the job. I still think uv is a good idea for devs who want to run the script locally, but that's a different story then.

ACK f252da7e6e1bbd0082fd43c4ffabfa90abafb248